1. Field of the Invention
This invention relates to a webbing stretching device for rendering a tensile force to an occupant restraining webbing to tightly fasten the same about an occupant in an emergency situation of a vehicle.
2. Description of the Prior Art
In a seatbelt system for protecting an occupant in an emergency situation of a vehicle, a webbing whose one end is retracted into a retractor is fastened about the occupant and the webbing restrains the occupant in an emergency situation of the vehicle.
The retractor for retracting this webbing renders a tension of a predetermined value to the webbing. However, in order not to give an excessive oppressive feeling to the occupant, a winding force is made to be relatively weak, being formed a slight gap between the webbing and the occupant. In consequence, such a disadvantage has been presented that after the webbing unwinding from the retractor has been stopped in an emergency situation of the vehicle, the occupant is moved by a value of the gap in a direction of a collision before he is reliably restrained by the webbing.
From this reason, heretofore, there has been proposed a webbing stretching device in which the intermediate portion of the webbing is moved perpendicularly to the longitudinal direction of the webbing to render a tensile force to the webbing or a takeup shaft of the retractor is rotated by a specially provided drive means to give a tensile force to the webbing. However, these stretching devices are all large-sized and complicated in construction, thereby necessitating change the conventional retractors in construction to a considerable extent.